/**
 * @nahisaho/yata-scale - Full-Text Index
 *
 * Full-text search index with tokenization and ranking
 */
import type { IndexStats } from '../types.js';
/**
 * Document to index
 */
export interface IndexDocument {
    readonly id: string;
    readonly content: string;
    readonly boost?: number;
}
/**
 * Search result
 */
export interface SearchResult {
    readonly id: string;
    readonly score: number;
    readonly highlights?: string[];
}
/**
 * Full-text search index with BM25 ranking
 */
export declare class FullTextIndex {
    private invertedIndex;
    private documentLengths;
    private documentCount;
    private totalLength;
    private readonly k1;
    private readonly b;
    constructor();
    /**
     * Index a document
     */
    index(doc: IndexDocument): void;
    /**
     * Remove a document from index
     */
    removeDocument(id: string): boolean;
    /**
     * Search for documents
     */
    search(query: string, limit?: number): SearchResult[];
    /**
     * Fuzzy search using Levenshtein distance
     */
    fuzzySearch(query: string, maxDistance?: number, limit?: number): SearchResult[];
    /**
     * Tokenize text
     */
    private tokenize;
    /**
     * Simple stemmer (Porter-like for English)
     */
    private stem;
    /**
     * Calculate term frequencies
     */
    private calculateTermFrequencies;
    /**
     * Levenshtein distance for fuzzy matching
     */
    private levenshteinDistance;
    /**
     * Clear the index
     */
    clear(): void;
    /**
     * Get document count
     */
    get size(): number;
    /**
     * Get term count
     */
    get termCount(): number;
    /**
     * Get index statistics
     */
    getStats(): IndexStats;
    /**
     * Estimate memory size
     */
    private estimateSize;
}
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